1. Field of the Invention
The present invention disclosed herein relates to a semiconductor device and a method of manufacturing the same. More particularly, the present invention relates to a semiconductor nonvolatile memory device exhibiting improved electrical operation and a method of manufacturing the same.
2. Description of the Related Art
In general, semiconductor memory devices may be classified into volatile memory devices and nonvolatile memory devices. The volatile memory devices may need power supply to retain data, while the nonvolatile memory devices, e.g., a flash memory device, may retain data without power. The flash memory device may refer to a highly-integrated nonvolatile memory device that may include both an erasable programmable read only memory (EPROM) and an electrically erasable programmable read only memory (EEPROM).
The conventional flash memory device may need a p-type floating gate layer for excellent RTS (room temperature storage) characteristics. In particular, the p-type floating gate layer may facilitate formation of a depletion region between the p-type floating gate layer and a tunneling insulation layer, thereby minimizing electron leakage from the floating gate layer through the tunneling insulation layer into a semiconductor substrate. The conventional p-type floating gate layer may be formed between device isolation regions via a SAG (Self Align Gate) process.
However, the use of a conventional SAG process may cause formation of ridges or voids in the p-type floating gate layer during manufacturing thereof and, thereby, degrade the overall electrical operation of the nonvolatile memory device.
Accordingly, there exists a need for an improved nonvolatile memory device with improved electrical operation and method of manufacturing the same.